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One layer closure of chimney-like structure


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Posted · One layer closure of chimney-like structure

Cura is generating incorrect GCode. It is closing off an area that should be open.

 

I have what is essentially a duct/chimney running from the bottom of a structure into the module of it. The structure is much like a house, and the duct/chimney is open on the ground level and runs up into the structure, where it dead-ends. The intent is to have a cavity in the structure that can be accessed from the opening in the floor.

 

The duct is being rendered mostly correctly. But on one specific layer the extruder is filling in the duct, adding a one layer floor, complete with supports.

 

I have triple checked the STL file using an STL viewer and there is no floor inside of the duct.

 

I can find no plausible reason why this floor within the duct is being added gratuitously.

 

I have tried simplifying the design br cropping out walls and other features of the block. When I remove one particular wall...located far far away...then the problem ceases to happen.

 

Any thoughts about this? Is it a known bug, or does some situation cause this?

 

 

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    Posted · One layer closure of chimney-like structure

    Attached are files. I have reduced my model as much as I can while the problem still reproduces.

     

    In the first image you will see highlighted in yellow what the model looks like on the bottom In the second image you see what Cura is producing for the first layer. Notice that the hole is missing in Cura's slicing of the first layer.

     

    Notice in the model a line that is on the right-facing wall about 10% up from the floor. I'd this line is deleted, the problem disappears. However, I have carefully looked inside the model and it is not forming a floor or compartment...it's just a line. Similarly, deleting other structures like the girl on the end also causes the problem to disappear.

     

    Also attached are two partial X-Ray views showing that there is no floor or structure that intersects the "chimney with the curved top" to create any sort of a floor.

     

    -----

     

    Any help that can be offered with this would be appreciated. I have spent a long time on this. The actual model is very complex, and recreating it would take a month or so...so I would love to know what either the problem is or what the workaround is. Do I have a bad setting? Is this a known bug?

     

     

    1573085018_CPD2019-11-25X-3d.thumb.png.2b5ec6238ba51598e4f3dad4f9aad31e.png 1480059684_CPD2019-11-25X.thumb.png.322fdbe94f1d54963eb2df843462d6d5.png

    616745221_CPD2019-11-25X-X1.thumb.png.ad587bd12a18574bdc20e192b9f6c6b0.png

    861612741_CPD2019-11-25X-X2.thumb.png.da27a4a617c60c45fa5f00becabe0f3c.png

    CPD 2019-11-25X.3mf CPD 2019-11-25X.stl CPD 2019-11-25X.skp.zip

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    Posted · One layer closure of chimney-like structure

    The model has a lot incorrect normals. Even one that on the same face. I recall reading somewhere that cura doens't affect by normals, but I guess I read wrong.

    Here is the model after fixing the normals.

     

    image.thumb.png.5e0ee70527affb1fb9bb99f9dd5dc988.png

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    Posted · One layer closure of chimney-like structure

    As @alexjx says, the problem appears to be with the model's normals. If you install the Mesh Tools plugin from the Marketplace, you have an option to fix model normals from within Cura. Here's your model, twice. The one on the right has had its normals fixed by the plugin, the other, not.

     

    Screenshot_2019-11-26_07-30-41.thumb.png.a46ca7dccf6de0884db15bf2015eef08.png

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    Posted · One layer closure of chimney-like structure

    Wow!

     

    I can't express enough gratitude. I spent days struggling with this. I didn't know about this tool, I will get it.

     

    I appreciate your time, the help diagnosing it, and sharing this tool which I didn't know about or know that I needed.

     

    Thanks again.

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